Cross-Modal Enhancement of Speech Detection in Young and Older Adults: Does Signal Content Matter?
Year: 2011
Type: article
Abstract: In Brief Objective: The purpose of the present study was to examine the effects of age and visual content on cross-modal enhancement of auditory speech detection. Visual content consisted of three clearly distinct types of visual information: an unaltered video clip of a talker's face, a low-contrast version of the same clip, and a mouth-like Lissajous figure. It was hypothesized that both young and older adults would exhibit reduced enhancement as visual content diverged from the original clip of the talker's face, but that the decrease would be greater for older participants. Design: Nineteen young adults and 19 older adults were asked to detect a single spoken syllable (/ba/) in speech-shaped noise, and the level of the signal was adaptively varied to establish the signal-to-noise ratio (SNR) at threshold. There was an auditory-only baseline condition and three audiovisual conditions in which the syllable was accompanied by one of the three visual signals (the unaltered clip of the talker's face, the low-contrast version of that clip, or the Lissajous figure). For each audiovisual condition, the SNR at threshold was compared with the SNR at threshold for the auditory-only condition to measure the amount of cross-modal enhancement. Results: Young adults exhibited significant cross-modal enhancement with all three types of visual stimuli, with the greatest amount of enhancement observed for the unaltered clip of the talker's face. Older adults, in contrast, exhibited significant cross-modal enhancement only with the unaltered face. Conclusions: Results of this study suggest that visual signal content affects cross-modal enhancement of speech detection in both young and older adults. They also support a hypothesized age-related deficit in processing low-contrast visual speech stimuli, even in older adults with normal contrast sensitivity. This investigation considered possible age-related differences in cross-modal enhancement during the detection of audio speech paired with varying amounts of visual content. Young and older adults were asked to detect the syllable /ba/ in noise during an adaptive two-alternative forced-choice test. The young adults demonstrated increasing cross-modal enhancement with increasing amounts of visual content, whereas the older adults only showed cross-modal enhancement when the clear, unaltered video was paired with the audio. Results suggested that signal content does affect cross-modal enhancement in a detection task. They also support a hypothesized age-related deficit in processing low-content visual speech stimuli.
Source: Ear and Hearing
Institution: Washington University in St. Louis
Language: English
Subfield: Experimental and Cognitive Psychology
Field: Psychology
Domain: Social Sciences
Open Access status: green
Funder: National Institute on Aging
OpenAlex ID: W2062987027